Joe they have little vials I forget who makes them I will look it up. But you put a .1 in a little vial with solution and it changes to a purple colour, the darker purple the more CBD. I think
@hyroot may have tried them. I could be mis-remembering but I am pretty sure a few users here won them off the Adam Dunn show.
http://www.hightimes.com/read/high-buy-cbscientific-personal-analytics-thc-and-cbd-test-kit
If I remember correct you can test fresh buds right off the plant. It's not going to give you a number % but you could compare strains and take the best one to get tested properly with accuracy.
I'd look into them before that Mydx thing. There's some threads on here with the mydx not having great results. Quite a few users here have one and I think there has been only 1 person to date post results at all.
I'm a pessimist
when something that awesome sounding comes out I think it's too good to be true. They had a rep here for an afternoon, he didn't get received well
He couldn't answer anyone's questions.